Air inlet guide structure and ultrasonic gas meter flow channel assembly using same

Abstract

The utility model belongs to ultrasonic flowmeter technical field discloses a kind of air intake flow guide structure and the ultrasonic gas meter flow passage assembly of its application, the air intake flow guide structure includes: for connecting in the air intake end of flow passage body conical flow guide cover and the first ultrasonic transducer installation part being arranged in conical flow guide cover axis, the first ultrasonic transducer installation part is fixedly connected with conical flow guide cover, conical flow guide cover is coaxial with flow passage body and is connected in the air intake end of flow passage body, first ultrasonic transducer installation part is located in conical flow guide cover central axis position, annular drainage passage is formed between conical flow guide cover and first ultrasonic transducer installation part.The air intake flow guide structure is matched by conical flow guide cover and first ultrasonic transducer installation part, improves the flow field stability in ultrasonic gas meter flow passage assembly, and flow fluctuation is significantly reduced.

Description

Technical Field

[0001] This utility model relates to the field of ultrasonic meter technology, and in particular to an air inlet guide structure and its application in ultrasonic gas meter flow channel components. Background Technology

[0002] Gas meters are widely used in various technical fields. Based on their principles, gas meters can be divided into many different types. Among them, ultrasonic gas meters are increasingly widely used due to their advantages such as having no moving mechanical parts, wide measuring range, and high accuracy.

[0003] This type of gas meter measures flow rate based on the time difference of flight of the upstream and downstream components along the ultrasonic transmission path. During the process, gas sound velocity information is incorporated, and the flow rate is measured by the combined effect of the flow field and the sound field. According to the ultrasonic measurement path, existing ultrasonic gas meters can be divided into refractive and through-beam types.

[0004] From a technical perspective, flow field stability is a crucial prerequisite for ensuring measurement accuracy. When the airflow is turbulent or unevenly distributed, the chaotic flow field cannot accurately measure the velocity information of the gas medium. Existing through-beam ultrasonic gas meters still face significant challenges. Their sensor layout is prone to causing local acceleration or vortex phenomena in the flow field, especially under high flow conditions. This velocity fluctuation directly reduces the stability of the measurement results. Specifically, when the airflow passes through the through-beam sensor area, the fluid experiences nonlinear disturbances due to the sensor structure. These disturbances amplify exponentially with increasing flow rate, resulting in large fluid velocity fluctuations and poor stability of the flow measurement results. The inlet structure design of existing through-beam ultrasonic gas meters is insufficient to solve these problems.

[0005] Therefore, existing technologies need further improvement. Utility Model Content

[0006] To address the aforementioned issues, this invention provides an air intake guide structure and its application in an ultrasonic gas meter flow channel assembly. This air intake guide structure is not only simple in structure but also improves the flow field stability of the through-beam ultrasonic gas meter module, significantly reducing the fluctuation range of the flow rate.

[0007] To address the above problems, this application provides the following technical solution: In a first aspect, this application provides an air intake guiding structure for use in a through-beam ultrasonic gas meter module, comprising: a conical guide shroud for connecting to the air intake end of the flow channel body, and a first ultrasonic transducer mounting part disposed at the axis of the conical guide shroud. The first ultrasonic transducer mounting part is fixedly connected to the conical guide shroud, the conical guide shroud is coaxial with the flow channel body and connected to the air intake end of the flow channel body, the first ultrasonic transducer mounting part is located at the central axis of the conical guide shroud, and an annular flow channel is formed between the conical guide shroud and the first ultrasonic transducer mounting part.

[0008] Optionally, in the air intake guide structure, the first ultrasonic transducer mounting part includes: an arc-shaped outer cover that is interlocked with each other and a hollow frustum-shaped mounting seat, the inner cavities of the frustum-shaped mounting seat and the arc-shaped outer cover enclosing each other to form an ultrasonic transducer mounting cavity; the outer conical wall of the frustum-shaped mounting seat is parallel to the inner wall of the conical guide shroud.

[0009] Optionally, in the air intake guide structure, the inner wall of the bottom of the inner cavity of the arc-shaped outer cover extends axially to form an ultrasonic transducer mounting groove, and the inner wall of the frustum-shaped mounting base extends inward to form a snap-fit ​​part for engaging with the ultrasonic transducer mounting groove; the arc-shaped outer cover is a spherical surface, a conical surface, or a bullet-shaped surface, and the snap-fit ​​part is a limiting ring.

[0010] Optionally, in the air intake guide structure, the outer wall of the frustum-shaped mounting base extends outward symmetrically with first connecting ribs, and the outer edge of the conical guide shroud extends outward to form a connecting rod mounting part for connecting with the first connecting ribs. The end of each first connecting rib is detachably connected to each connecting rod mounting part of the conical guide shroud.

[0011] Optionally, in the air intake guide structure, the first connecting rib is arranged radially, and the connecting rod mounting part of the conical guide shroud is provided with a second slot for engaging with the outer end of the first connecting rib; the bottom wall of the outer end of the first connecting rib and the second slot are respectively provided with connecting holes for fastener engagement.

[0012] Optionally, in the air intake guide structure, first protrusions are symmetrically arranged on the inner side of the arc-shaped outer cover, and the conical sidewall of the frustum-shaped mounting base is provided with a first groove that engages with the first protrusions; the first protrusions extend axially, and the end of the first protrusions forms a wedge-shaped protrusion in the direction of the first groove.

[0013] Optionally, in the air intake guide structure, the inner outer edge of the arc-shaped outer cover is provided with a first positioning protrusion or a first positioning groove along the circumferential direction, and the outer outer edge of the frustum-shaped mounting base is provided with a second positioning groove that is inserted into the first positioning protrusion or a second positioning protrusion that is inserted into the first positioning groove.

[0014] Optionally, the distance t between the inner end face of the frustum-shaped mounting base and the outer end face of the flow channel body is set as: 2 / 8D < t < 3 / 8D, where D is the inner cavity diameter of the flow channel body; the taper A of the conical guide shroud is greater than arctan(d / 2t), where d is the diameter at the widest point of the first ultrasonic transducer mounting part, and taper A is the angle formed by the side wall of the conical guide shroud and the central axis of the flow channel; the relationship between the length L of the conical guide shroud, the distance t between the inner end face of the frustum-shaped mounting base and the outer end face of the flow channel body, and the taper A satisfies the following relationship: L*cosA ≥ (1.8~2.2)t.

[0015] Secondly, this application also provides a through-beam ultrasonic gas meter flow channel assembly, which includes: a tubular flow channel body, and the aforementioned air inlet guide structure is fixedly disposed at the air inlet end of the flow channel body.

[0016] Optionally, in the ultrasonic gas meter flow channel assembly, a partition plate extends vertically outward from the outer wall of the flow channel body near the outlet end, a circuit board mounting plate is disposed on the top of the flow channel body, one side of the circuit board mounting plate is integrally formed or fixedly connected to the partition plate, the bottom of the circuit board mounting plate is integrally formed or fixedly connected to the flow channel body, and a circuit board mounting groove is provided on the circuit board mounting plate.

[0017] Optionally, in the ultrasonic gas meter flow channel assembly, the air outlet end of the flow channel body is further provided with a trumpet-shaped air outlet guide structure, and a second ultrasonic transducer mounting seat is provided on the outer side of the air outlet guide structure at the axial position. The second ultrasonic transducer mounting seat is fixedly connected to the air outlet guide structure through a connecting part, and the first ultrasonic transducer mounting seat and the second ultrasonic transducer mounting seat are coaxially arranged.

[0018] This utility model has the following beneficial effects: 1. In the air intake guiding structure provided in this application, the annular guiding channel formed between the conical guide shroud and the first ultrasonic transducer mounting part is arranged around the outer periphery of the side of the ultrasonic transducer, resulting in a smoother flow path without inflection points. This avoids disturbances caused by inflection points and improves fluid stability. Furthermore, because the annular guiding channel is wider and the flow path is smoother, it can also be used to measure ultrasonic flow meters with larger flow rates. The arc-shaped outer cover allows the fluid at the air intake end to smoothly transition into the annular guiding channel along the smooth arc surface, effectively avoiding the problem of interference between the reverse flow and the intake flow caused by the fluid acting on the plane, thus improving the flow field stability.

[0019] 2. The ultrasonic gas meter flow channel assembly provided by this utility model improves the flow field stability of the gas meter module and significantly reduces the fluctuation range of the flow rate by adopting the above-mentioned air inlet guiding structure. In the ultrasonic gas meter flow channel assembly, the ultrasonic transducer and the first ultrasonic transducer mounting part have a simple structure and are easy to install. Attached Figure Description

[0020] Figure 1 This is the three-dimensional structure of the air intake guide structure in Example 1; Figure 2 This is an exploded view of the air intake guide structure in Example 1; Figure 3 This is a three-dimensional structural schematic diagram of the ultrasonic air meter flow channel assembly in Example 2; Figure 4 This is a top view of the ultrasonic air meter flow channel assembly of Example 2; Figure 5 for Figure 4 AA section view; Figure 6 This is an exploded view of the ultrasonic gas meter flow channel assembly of Example 2. Figure 1 ; Figure 7 This is an exploded view of the ultrasonic gas meter flow channel assembly of Example 2. Figure 2 ; Figure 8 The flow fluctuation analysis results are for the ultrasonic gas meter module used as a control group. Figure 9 The results of flow fluctuation analysis of the ultrasonic gas meter flow channel assembly in Example 2 are shown. The reference numerals in the attached drawings are explained as follows: Flow channel body 1, Annular rectification structure 11, Connecting column 111, Air inlet guide structure 2, Conical guide cover 21, First connecting rib mounting part 211, First ultrasonic transducer mounting part 22, Arc-shaped outer cover 221, Ultrasonic transducer mounting groove 221a, First locking protrusion 221b, First positioning groove 221c, Frustum-shaped mounting seat 222, Locking part 222a, First locking groove 222b, Second positioning protrusion 222c, First connecting rib 222d, Air outlet guide structure 3, Air outlet buffer chamber 4, Separator plate 41, Buffer chamber shell 42, Air outlet pipe 43, Circuit board mounting plate 5, Second ultrasonic transducer mounting seat 6, Annular mounting seat body 61, Locking block 612, Second connecting rib 62, Third locking groove 621, Outer cover 63, Notch 631, Locking hole 632. Detailed Implementation

[0021] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0022] It should be noted that when an element is described as being "fixed to" another element, it can be directly on the other element, or one or more intermediate elements may exist between them. When an element is described as being "connected to" another element, it can be directly connected to the other element, or one or more intermediate elements may exist between them. The terms "vertical," "horizontal," "left," "right," "upper," "lower," "inner," "outer," and "bottom," etc., used in this specification to indicate orientation or positional relationships are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0023] Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "and / or" as used in this specification includes any and all combinations of one or more of the associated listed items. Furthermore, technical features involved in the different embodiments of the invention described below may be combined with each other as long as they do not conflict with each other.

[0024] Example 1 like Figures 1-2 As shown, this embodiment provides an air inlet guiding structure applied to a through-beam ultrasonic gas meter module. The structure of the ultrasonic gas meter module can be referred to... Figures 3-7 .

[0025] In this embodiment, the air intake guide structure includes: a conical guide shroud 21 for connecting to the air intake end of the flow channel body and a first ultrasonic transducer mounting part 22 disposed at the axis of the conical guide shroud. The first ultrasonic transducer mounting part 22 is fixedly connected to the conical guide shroud. The conical guide shroud is coaxial with the flow channel body and connected to the air intake end of the flow channel body. The first ultrasonic transducer mounting part 22 is located at the central axis of the conical guide shroud. An annular flow channel is formed between the conical guide shroud and the first ultrasonic transducer mounting part.

[0026] The air intake guide structure 2 includes: a conical guide shroud 21 and a first ultrasonic transducer mounting part 22 fixedly connected to the conical guide shroud. The conical guide shroud is coaxial with the flow channel body and connected to the air intake end of the flow channel body. The first ultrasonic transducer mounting part 22 is located at the central axis of the conical guide shroud (a second ultrasonic transducer mounting seat 6 is provided along the axis on the outer side of the air outlet end of the ultrasonic gas meter flow channel assembly used therein, and the two ultrasonic transducer mounting parts are coaxially opposite each other). The outer wall of the conical guide shroud is parallel to the inner wall of the conical guide shroud, and an annular guide channel is formed between the conical guide shroud and the outer wall of the first ultrasonic transducer mounting part.

[0027] In use, first install the air inlet guide structure onto the air inlet end of the flow channel body of the ultrasonic gas meter assembly (another ultrasonic transducer mounting base is installed at the air outlet end of this flow channel body). During operation, the gas to be measured enters the flow channel body from the annular guide channel of the air inlet guide structure and finally flows out from the outlet of the flow channel body, thus achieving fluid flow rate measurement within the flow channel body. During this process, the fluid flow direction is parallel to the ultrasonic wave propagation direction.

[0028] Since the annular flow channel formed between the conical flow guide and the first ultrasonic transducer mounting part is arranged around the outer periphery of the side of the ultrasonic transducer, the flow path is smoother and there are no inflection points. Therefore, the disturbance caused by inflection points is avoided, and the fluid stability is improved. In addition, since the annular flow guide is wider and the flow path is smoother, it can also be used to measure ultrasonic flow meters with larger flow rates.

[0029] Specifically, the first ultrasonic transducer mounting part 22 includes: an interlocking arc-shaped outer cover 221 and a hollow frustoconical mounting base 222. The inner cavities of the frustoconical mounting base 222 and the arc-shaped outer cover 221 enclose an ultrasonic transducer mounting cavity. The diameter of the frustoconical mounting base gradually decreases towards the flow channel body. The outer conical wall of the frustoconical mounting base is parallel to the inner wall of the conical flow guide.

[0030] Preferably, the arc-shaped outer cover 221 is hemispherical. In other embodiments, it can also be about 1 / 2 to 3 / 4 of a sphere, or it can be designed as a conical surface or a bullet-shaped surface. The hemispherical arc-shaped outer cover allows the fluid at the air inlet to smoothly transition into the annular guide channel along the smooth spherical surface, effectively avoiding the problem of interference between the reverse flow formed by the fluid acting on the plane and the airflow in the intake, and the generation of vortices.

[0031] To facilitate the installation of ultrasonic transducers, such as Figure 7 As shown, the inner wall of the bottom of the inner cavity of the arc-shaped outer cover 221 extends axially to form an ultrasonic transducer mounting groove 221a, as... Figure 6As shown, the inner wall of the frustoconical mounting base 222 extends inward to form a snap-fit ​​portion 222a for engaging with the ultrasonic transducer mounting slot. Through the assembly of the ultrasonic transducer mounting slot 221a and the snap-fit ​​portion 222a, a receiving slot for the first ultrasonic transducer is formed inside both.

[0032] In this embodiment, the snap-fit ​​portion 222a is a limiting ring.

[0033] To facilitate the installation and disassembly of the ultrasonic transducer, multiple first protrusions 221b are symmetrically arranged on the inner side of the curved outer cover 221, and the conical sidewall of the frustum-shaped mounting base is provided with a first groove 222b that engages with the first protrusions. The first protrusions extend axially, and their ends form wedge-shaped protrusions towards the first grooves. The engagement of the first protrusions 221b and the first grooves 222b enables rapid assembly of the frustum-shaped mounting base and the curved outer cover.

[0034] The inner outer edge of the arc-shaped outer cover 221 is provided with at least one first positioning protrusion or first positioning groove 221c along the circumferential direction, and the outer edge of the frustum-shaped mounting base is provided with a second positioning groove or a second positioning protrusion 222c that is inserted into the first positioning protrusion.

[0035] During operation, the arc-shaped outer cover and the frustum-shaped mounting base can be quickly and accurately aligned through the cooperation of the positioning protrusion and the corresponding positioning groove, and the two can be further stably connected through the cooperation of the aforementioned first locking protrusion and first locking groove.

[0036] Preferably, the distance t between the inner end face of the frustum-shaped mounting base and the outer end face of the flow channel body is set to: 2 / 8D < t < 3 / 8D, where D is the inner cavity diameter of the flow channel body. The angle A (i.e., taper) formed by the side wall of the conical guide shield and the central axis of the flow channel is greater than arctand / 2t, and d is the diameter of the widest part of the first ultrasonic transducer mounting section, i.e., the diameter of the arc-shaped outer cover. Under the above conditions, this structural design avoids the generation of detached vortices at the rear section of the transducer, and prevents the generation of eddies due to reverse pressure gradients caused by sudden changes in flow velocity, which would affect the uncertainty of the measurement test. It also ensures uniform flow velocity in the central area and surrounding areas of the flow channel body cross-section, and the measurement section can represent the entire cavity area, resulting in high fluid stability and improved stability and accuracy of the measurement results.

[0037] If t is too large, the flow velocity in the central region behind the frustum-shaped mounting base will be too slow compared to the surrounding regions, easily introducing more variables. The flow velocity will be uneven across the cross-section of the flow channel, making the fluid velocity in the ultrasonic measurement area unrepresentative and leading to inaccurate measurement results. If t is too small, most of the fluid flowing in from the annular conical guide channel will flow directly into the flow channel body from the outside, leaving less fluid reaching the central region corresponding to the ultrasonic transducer. This results in a slow flow velocity, a large difference in flow rate between the central and surrounding regions, and unrepresentative measurement results.

[0038] If the angle between the sidewall of the conical flow deflector and the central axis of the flow channel is too large, the flow velocity in the central region behind the frustum-shaped mounting base will be higher than that in the surrounding region, leading to an unstable flow field, large fluctuations in measurement results, and unrepresentative results. If the angle between the sidewall of the conical flow deflector and the central axis of the flow channel is too small, the fluid at the inlet end will tend to flow through the outer periphery of the flow channel body, resulting in uneven flow rates between the central and surrounding regions, a gradient velocity, and the easy formation of vortices in the central region, affecting the stability of the flow field.

[0039] More preferably, the relationship between the length L of the conical shroud, the distance t between the inner end face of the frustum-shaped mounting base and the outer end face of the flow channel body, and the taper A satisfies the following relationship: L×cosA≥(1.8~2.2)t. Test results show that under this condition, the turbulence is smaller.

[0040] The outer wall of the frustoconical mounting base extends symmetrically outward to form a first connecting rib 222d, and the outer edge of the conical air guide extends outward to form a first connecting rib mounting portion 211 for connecting with the first connecting rib. The first connecting ribs are arranged radially, and the first connecting rib mounting portion 211 of the conical air guide is provided with a second slot for engaging with the outer end of the first connecting rib. Corresponding connecting holes for fastener engagement are provided on the bottom wall of the outer end of the first connecting rib and the second slot. The position of the first connecting rib mounting portion 211 allows the inner wall of the conical air guide to present a complete conical surface structure without affecting its air guiding effect.

[0041] During installation, first insert the ultrasonic transducer into the ultrasonic transducer mounting slot 221a of the arc-shaped outer cover, then fasten the arc-shaped outer cover and the frustum-shaped mounting base together, then insert the first connecting rib 222d axially into the first connecting rib mounting part 211 of the conical guide shroud, and then install it into the above-mentioned connecting hole with fasteners (such as screws), thereby completing the assembly of the first ultrasonic transducer and the air intake guide structure.

[0042] Compared to existing through-beam gas meters, which suffer from poor stability due to significant turbulence, the air inlet guide structure provided in this embodiment effectively avoids disturbances caused by inflection points, improves fluid stability, and is applicable to the measurement of ultrasonic flow meters with larger flow rates.

[0043] Example 2 like Figures 3-7 As shown, this embodiment provides a through-beam ultrasonic gas meter flow channel assembly. The through-beam ultrasonic gas meter flow channel assembly includes: a flow channel body 1, an air inlet guide structure 2 as described in Embodiment 1 disposed at the air inlet end of the flow channel body, an air outlet guide structure 3 disposed at the air outlet end of the flow channel body, and an air outlet buffer cavity 4 provided with an air outlet. The air outlet end of the flow channel body 1 extends into the air outlet buffer cavity 4. A first ultrasonic transducer mounting part 22 is located at the central axis of the conical guide shroud, and a second ultrasonic transducer mounting seat 6 is disposed on the outer side of the air outlet guide structure 3 at the axis center. The two ultrasonic transducer mounting parts are coaxially opposite each other.

[0044] During operation, the gas to be measured enters the flow channel body through the inlet guide structure, enters the outlet buffer chamber along the outlet guide structure, and flows out along the outlet, completing the flow rate measurement of the fluid within the flow channel body.

[0045] In this embodiment, for ease of loading, unloading and use, the air outlet buffer chamber 4 is assembled from a partition plate 41 and a buffer chamber shell 42. The partition plate is formed by extending vertically outward from the outer wall of the flow channel body 1 near the air outlet end. The air outlet pipe 43 is located at the top of the buffer chamber shell, and the air inlet guide structure and the second ultrasonic transducer mounting seat are located inside the air outlet buffer chamber.

[0046] like Figure 7 As shown, in this embodiment, the second ultrasonic transducer mounting base includes an annular mounting base body 61 with an internal stepped transducer receiving groove and an outer cover 63 that is fastened to the mounting base body from the outside. Three second connecting ribs 62 are symmetrically arranged on the outer periphery of the mounting base body, and three connecting parts that are inserted and cooperate with the second connecting ribs are provided at the outer end of the air outlet guide structure.

[0047] In this embodiment, the connecting part is a connecting post 111 extending along the axial direction, and the end of the second connecting rib is provided with a third slot 621 that is inserted and engaged with the connecting post.

[0048] The outer cover 63 is an annular cover with a notch 631. The notch is designed to allow the wires on the ultrasonic transducer, once installed, to pass through the notch and connect smoothly to the metering circuit board.

[0049] The outer cover has connecting ears on its side for snapping with the mounting base body; the connecting ears have snap-fit ​​holes 632 for engaging with the mounting base body. Correspondingly, the outer circumferential surface of the corresponding end of the mounting base body has snap-fit ​​blocks 612 for engaging with the snap-fit ​​holes. The snap-fit ​​between the outer cover and the mounting base body is achieved through the engagement of the snap-fit ​​blocks and the snap-fit ​​holes, thus completing the installation of the second ultrasonic transducer.

[0050] To improve the rectification effect within the flow channel body, an annular rectification structure 11 is provided extending axially along the inner cavity of the flow channel body. The annular rectification structure includes multiple concentrically arranged annular partition tubes. The annular partition tubes are connected to adjacent annular partition tubes through a third connecting rib, and the outermost annular partition tube is connected to the inner wall of the flow channel body through a third connecting rib.

[0051] To facilitate the installation of the circuit board, a circuit board mounting plate 5 is set on the top of the flow channel body. One side of the circuit board mounting plate is integrally formed or fixedly connected to the partition plate, and the bottom of the circuit board mounting plate is integrally formed or fixedly connected to the flow channel body. The circuit board mounting plate is provided with a circuit board mounting groove.

[0052] Optionally, to reduce production costs and improve product lightweighting, the ultrasonic air meter module is made of plastic, and the conical air guide cover, flow channel body, air inlet guide structure, and partition plate can be set as an integrated structure.

[0053] Test Implementation Examples Flow fluctuation and repeatability analysis were performed on the ultrasonic gas meter flow channel assembly of Example 2, and a control group was set up simultaneously. Control group: The air inlet of the ultrasonic gas meter flow channel assembly adopts a traditional horn-shaped guide ring (refer to the air outlet guide structure of Example 1), and other settings are the same as the structure of Example 2.

[0054] 1. Testing equipment: Name: Sonic Nozzle Gas Meter Testing Device; Model: MJ2210-06B; Accuracy Class: 0.33; Flow Range: (0.06-65) m³ / s 3 / h, flow rate stability: ≤0.1%, manufacturer: Haiyan Meijie Test Instruments Co., Ltd.

[0055] 2. Testing methods and conditions (1) Method for measuring flow pulsation: Test at a certain flow rate, take the measured flow rate value of the instrument every 125ms, capture time for more than 100s, and plot the data as a flow curve. The difference between the maximum and minimum values ​​of the data is defined as the flow pulsation value, and the discreteness of the data represents the standard deviation.

[0056] Formula for calculating standard deviation: ,in, For sample data points, Let n be the sample mean and n be the sample size.

[0057] (2) Method for determining repeatability: The same test environment, the same operation method, and the same operators are used to conduct 6 repeated tests on a certain flow point to obtain the error of the 6 test values. The difference between the maximum and minimum values ​​of the error is defined as the repeatability test result of the flow point.

[0058] The indication error is compared using the cumulative quantity comparison method: the cumulative quantity of the standard device is compared with the cumulative quantity of the meter being measured over a certain period of time, and the formula is as follows: Indication error: E = (Q 被测表 -Q 标准表 ) / Q 标准表 *100%; where Q 标准表 For the cumulative amount in the standard table, Q 被测表 The cumulative value of the measured meter is given by the ambient temperature (20±2)℃ and humidity ≥35%RH.

[0059] 3. Test Results and Analysis (1) Flow pulsation experiment: Figure 8 The analysis results of the flow pulsation (i.e., fluctuation) of the ultrasonic gas meter module in the control group show that the flow fluctuation value of the ultrasonic gas meter module in the control group is 2m. 3 / h, standard deviation 0.43, large fluctuation, measurement results are unstable.

[0060] Figure 9 The flow fluctuation analysis results of the ultrasonic gas meter module in Example 1 show a flow fluctuation value of 0.7 m3 / h and a standard deviation of 0.09. Compared with the control group, its flow stability is improved by 60%.

[0061] (2) Results of repeatability experiments The repeatability results of the ultrasonic gas meter module in Example 2 are shown in Table 1 below. These results demonstrate that the ultrasonic gas meter module provided in this application has good repeatability and is applicable to the measurement of a wide range of flow rates, including high and low flow rates.

[0062] Table 1. Repeatability results of the indication error of the ultrasonic gas meter module in Example 1

[0063] Therefore, it can be seen that the measurement results of the ultrasonic gas meter module provided in this embodiment are significantly improved in terms of stability and flow fluctuation, and it can be applied to the measurement of flow over a wide range.

[0064] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. It is understood that those skilled in the art can make equivalent substitutions or modifications based on the technical solution and concept of this utility model, and all such modifications or substitutions should fall within the protection scope of the appended claims.

Claims

1. An air inlet guiding structure applied to a through-beam ultrasonic gas meter module, characterized in that, include: A conical flow guide shroud is used to connect to the air inlet end of the flow channel body of the ultrasonic gas meter module, and a first ultrasonic transducer mounting part is disposed in the conical flow guide shroud. The first ultrasonic transducer mounting part is fixedly connected to the conical flow guide shroud. The conical flow guide shroud is coaxial with the flow channel body and connected to the air inlet end of the flow channel body. The first ultrasonic transducer mounting part is located at the central axis of the conical flow guide shroud. An annular flow channel is formed between the conical flow guide shroud and the first ultrasonic transducer mounting part.

2. The air intake guide structure according to claim 1, characterized in that, The first ultrasonic transducer mounting part includes: an arc-shaped outer cover that interlocks with each other and a hollow frustum-shaped mounting base. The inner cavities of the frustum-shaped mounting base and the arc-shaped outer cover enclose an ultrasonic transducer mounting cavity. The outer conical wall of the frustum-shaped mounting base is parallel to the inner wall of the conical guide shroud.

3. The air intake guide structure according to claim 2, characterized in that, The inner wall of the inner cavity of the arc-shaped outer cover extends axially to form an ultrasonic transducer mounting groove, and the inner wall of the frustum-shaped mounting base extends inward to form a locking part for engaging with the ultrasonic transducer mounting groove. The locking part is a limiting ring. The arc-shaped outer cover is a spherical surface, a conical surface, or a bullet-shaped surface.

4. The air intake guide structure according to claim 2, characterized in that, The outer wall of the frustoconical mounting base extends outward symmetrically with first connecting ribs, and the outer edge of the conical fairing extends outward to form a connecting rod mounting part for connecting with the first connecting ribs. The end of each first connecting rib is detachably connected to each connecting rod mounting part of the conical fairing.

5. The intake guide structure according to claim 4, characterized in that, The first connecting rib is arranged radially, and the connecting rod mounting part of the conical guide shield is provided with a second slot for engaging with the outer end of the first connecting rib; the bottom wall of the outer end of the first connecting rib and the second slot are respectively provided with connecting holes for fastener engagement.

6. The intake guide structure according to claim 2, characterized in that, The inner side of the arc-shaped outer cover is symmetrically provided with first locking protrusions, and the conical sidewall of the frustum-shaped mounting base is provided with a first locking groove that engages with the first locking protrusions; the first locking protrusions extend axially, and the end of the first locking protrusions forms a wedge-shaped protrusion in the direction of the first locking groove.

7. The intake guide structure according to claim 6, characterized in that, The inner outer edge of the arc-shaped outer cover is provided with a first positioning protrusion or a first positioning groove along the circumferential direction, and the outer outer edge of the frustum-shaped mounting base is provided with a second positioning groove that is inserted into the first positioning protrusion or a second positioning protrusion that is inserted into the first positioning groove.

8. The air intake guide structure according to claim 2, characterized in that, The distance t between the inner end face of the frustum-shaped mounting base and the outer end face of the flow channel body is set as: 2 / 8D < t < 3 / 8D, where D is the inner cavity diameter of the flow channel body; the taper A of the conical guide shroud is greater than arctan(d / 2t), where d is the diameter of the widest part of the first ultrasonic transducer mounting section, and taper A is the angle formed by the side wall of the conical guide shroud and the central axis of the flow channel; the relationship between the length L of the conical guide shroud, the distance t between the inner end face of the frustum-shaped mounting base and the outer end face of the flow channel body, and the taper A satisfies the following relationship: L*cosA ≥ (1.8~2.2)t.

9. A through-beam type ultrasonic gas meter flow channel assembly, characterized in that, It includes: The tubular flow channel body has an air intake guide structure fixedly provided at the air intake end as described in any one of claims 1 to 8.

10. The ultrasonic gas meter flow channel assembly according to claim 9, characterized in that, A partition plate extends vertically outward from the outer wall of the flow channel body near the air outlet end. A circuit board mounting plate is set on the top of the flow channel body. One side of the circuit board mounting plate is integrally formed or fixedly connected to the partition plate. The bottom of the circuit board mounting plate is integrally formed or fixedly connected to the flow channel body. A circuit board mounting groove is provided on the circuit board mounting plate.

11. The ultrasonic gas meter flow channel assembly according to claim 10, characterized in that, The air outlet end of the flow channel body is also provided with a trumpet-shaped air outlet guide structure. A second ultrasonic transducer mounting seat is provided on the outer side of the air outlet guide structure at the axial position. The second ultrasonic transducer mounting seat is fixedly connected to the air outlet guide structure through a connecting part. The first ultrasonic transducer mounting seat and the second ultrasonic transducer mounting seat are coaxially arranged. An annular rectification structure is provided extending axially along the inner cavity of the flow channel body.

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